The comparative structure and organization of homologous gene regions from two species of non-human primates, the baboon and gorilla, will be studied in an effort to define sequences associated with globin gene regulation. Recombinant DNA "libraries" of genomic DNA for each species will be constructed and screened with human globin cDNA probes, and phage containing alpha, beta, delta, gamma, and epsilon gene sequences will be detected and cloned. Both the alpha and non-alpha gene clusters from these primates will be compared to those of humans with respect to the structural organization of both expressed and non-expressed DNA regions, particularly the putative regulatory areas inferred from studies of human thalassemias. The active delta gene of the gorilla, the silent delta gene of the baboon, and the occasionally active 3-alpha gene of the gorilla will each be studied by nucleotide sequence analysis. Detailed restriction mapping of the twin alpha and twin gamma loci in each species will be performed to determine whether they evolve in "concert" by unequal crossing-over and loss. The complexity and organization of repeated DNA families within the alpha and non-alpha gene clusters will be compared between species and with man to determine the evolutionary stability of such sequences and whether they can be correlated with gene function.